Additive for cement based mortars

ABSTRACT

AN ADDITIVE CONSISTING ESSENTIALY OF A MIXTURE OF A SULFONIC ACID GROUP-CONTAINING MELAMINE FORMALDEHYDE CONDENSATION PRODUCT AND A METAL STEARATE IS CAPABLE OF STRENGTHENING AND WATER-PROOFING CEMENT PRODUCTS.

United States Patent Patented Aug. 6, 1974 Ice 3,827,992 ADDITIVE FOR CEMENT BASED MORTARS Alois Aignesberger and Hans-Gunter Rosenbauer, Trostberg, Germany, assignors to Suddeutsche Kalkstickstoifmaterial. Therefore, one operation is saved as compared with sealing agents which are applied subsequently to the finished products.

The additives of the invention are useful for addition to Portland cement, dry batched aggregates and ready made wake fikhengesfinsdiafl.Tmstberg Germany mortars and are particularly suitable to addition to gun- No Drawing. Continuation-impart of abandoned appllcation Ser. No. 181,618, Sept. 17, 1971. This application '5 g i fi 1 Se N 347 894 o t ese concretes an topplngs 1s accor ing to e eve ci iiis i ri it y application hm: Iii-71 1 71 14 1371, of techmcal 37 509/71 Japan Oct. 5 1971 4 5 3' we ell, l0 COMPARATI E EXAMPLE Alig. 27, 1971, 10,855/71 Aust ralia, N ov. 1s, 1971, v

35 746/71 Standard prisms having a slump factor of 18111 cm,

Int. Cl. C08g 9/04 were produced with commercial Portland cement 275 (a US. Cl. 26021 5 Claims Portland cement which reaches a minimum compressive strength of 275 kg./cm. under the conditions specified in ABSTRACT OF THE DISCLQSURE DIN 1164 E, 1967). A sealing agent A, i.e., a commercial otassium aluminate-calcium stearate sealin a cut com- An additve consisting essentially of a mixture of a gosed of g g I sulfonic acid group-containing melamine formaldehyde condensation product and a metal stearate is capable of Parts y Weight strengthening and water-proofing cement products.

Potassium aluminate 1.5- Calcium hydroxide 1.6

This application is a continuation-impart of Ser. No. potassium hydroxide ,3 181,618 filed Stp. 17, 1971, and now abandoned. Sodium hydroxide 1,2

This invention relates to an additive for cement-based water 37,2 ggg gi ggg the production of watemmpervmus conwas included in some of the prisms. After one day the In the manufacture of water-proof cement products, and P g z fi from. tgelr molds 3 g particularly in the manufacture of cement-based ceiling, lmme S 6? 2 22 g 3 wall and floor finishes, it has already been suggested, e.g.,- atmPSP ere at 0 an 0 re anve or a er in Austrian Patent 192,838, to add to the cement mix lfi l b 1 1 b l water-soluble sealing agents based on alkali metal silicates, e ts are ta ate lmme late y e alkali metal aluminates, Fe(OH) fats, fatty acids, etc.

Sealants and adhesion agents as additives for cement g gg figg f g ggg fi fm or cement-containing mortars which consist of alkali metal Sealing agent A w mg) after; cmg) after; $151??? 2'3"/Z%*Zii'di?5ii1i7i "iif igi'eciititmmd mm mm mm been described iii Swiss Pat. 372,967 as well as iii West 8-2; 5 2g 3% it: German Provisional Pat. 1,057,002. aoIIIIIIIIIIIIIII 0152 20 47 63 13s The known sealing agents, however, have an unfavorable effect on the strength of the concrete or cement products.

It has been found that additives consisting essentially of 50-96% by weight, preferably 50-80% by weight of melamine formaldehyde condensation products which contain sulfonic acid groups and have a viscosity of 5-3 00 cp., measured in aqueous solution of 20% solids content, and 50-4% by weight, preferably 50-20% by weight metal stearate, which in addition may contain other known sealing agents, do not have this disadvantage. Surprisingly the additive of the invention exhibits both a strengthincreasing (Examples 1 and 2) and reinforced hydrophobic (Example 3) action on the products of cement-based mortars. A synergistic effect is noted in that the known strength-increasing effect on building materials of melamine formaldehyde condensation products containing sulfonic acid groups is further increased by the presence of EXAMPLE 1 Standard prisms having a slump factor of 18:1 cm. were produced with commercial Portland cement 275 in accordance with DIN 1164 E (1967 version), some with and some without additives. After a day the prisms were removed from their molds, some were tested immediately and the remainder were stored in a standard atmosphere at 20 C. and 65% relative humidity for later testing.

Additive B was a melamine-formaldehyde condensation product, available on the market as Melment L10 or F10, which contains sulfonic acid groups and has a viscosity of 10 cp., measured in an aqueous solution containing 20% by weight solid resin. Additive A was the sealing agent A described in the comparative example.

The results were:

stearates known as sealing agents, while at the same time gi gyggg 1113 55 gf flg fi fg the known water-repelling activity of the stearates added referred to cement Water/ cmfl) aitercm afte m f" F T B 1 :22 8; m 24 hours 28days The said melamine formaldehyde condensation products are available on the market. Their preparation is described "5' 8: ,3 g;

in Austrian Pat. 263,607. 10 5 0. 45 44 so 154 44s The metal stearates that are preferred in accordance 20 5 44 67 142 331 with the invention include alkaline-earth metal stearates,

zinc stearates, aluminum stearate and copper stearate. EXAMPLE 2 7 Up to 50% by weight of the content of metal stearate can be replaced by an aluminate, preferably an alkalimetal aluminate such as potassium aluminate.

The additive of the invention must be added to the cement-based mortar mixes during the mixing process to assure uniform distribution into the mixture of building Pairs of sandlime or calcium silicate brick cubes having an edge length of 4 cm. were bonded together with cement pastes prepared to have a water-cement value of 0.37

Additive C is a melamine-formaldehyde condensation product containing sulfonic acid groups and having a viscosity of 96 cp. (Measured at 20 C. with the Brookfield rotary viscosimeter, Model HAT, Spindle No. 1, 20 r.p.m.) This resin is available on the market under the name Melment L 300 or F 300, and contains 20% by weight solid resin.

The results were:

Additive, in percent by weight, Shear referred to cement strength (kg/cm!) Commercial zinc after stearate 1 day EXAMPLE 3 Additive, in percent by weight, referred to the weight of cement Water adsorption Neutral X Y (wt. B zinc stearate (seconds) percent) fPNPS tan-muse:

Further tests indicated the addition of 5% by weight of resin 13 referred to the cement or the cement-based mortar to be the economic optimum. However, the amount of the resin according to the invention can vary over a broad range and depends to some extent upon the special use of the cement or mortar. A suitable range is, for example, 2.5% to 20% by weight though these limits are merely exemplary and lower or higher amounts may be used.

We claim:

1. An additive for cement-based mortars consisting essentially of -96% by weight of a sulfonic acid groupcontaining melamine-formaldehyde condensation product having a viscosity of 5-300 cp., measured in aqueous solution containing 20% by weight solids, and of 504% by weight metal stearate or a mixture of metal stearate and up to 50%, based on the content of metal stearate, alkali-metal aluminate.

2. The additive defined in Claim 1, wherein the metal stearate is a member selected from the group consisting of alkaline-earth metal stearates, zinc stearate, aluminum stearate and copper stearate.

3. The additive defined in Claim 1, wherein the metal stearate is calcium stearate.

4. The additive defined in Claim 1, wherein the metal stearate is zinc stearate.

5. Method of producing a water-impervious product of concrete which comprises adding to a cement-based mortar an additive as defined in Claim 1 during the mixing process.

References Cited UNITED STATES PATENTS 2,611,713 9/1952 Glick 106-95 FOREIGN PATENTS 4,319,431 8/1968 Japan 106-95 263,607 7/1968 Austria 106-95 192,838 11/1957 Austria 106-95 372,967 12/1963 Switzerland 106-95 1,057,002 11/1967 W. Germany 106-95 1,185,971 1/1965 W. Germany 106-95 MAURICE J. WELSH, Primary Examiner R. W. GRIFFIN, Assistant Examiner US. Cl. X.R. 106-95 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,827 ,992 Dated August 6, 1974 Inven fl Alois Aianesbereer et a1.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Heading:

After "Claims Priority, application" replace "Great Britain. ..Australia, Nov. 16, 1971, 35,509/71" by -Germany, October 7, 1970, P. 20 49 158.1",

Signed and sealed this 29th day of October 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM-DC 60376-P69 U.S. GOVERNMENT PRINTING OFFICE: I969 0-886-33l.

FORM Po-1050 (10-69) 

